Prison reform charity the Howard League says that the increase in contraband, including drugs and mobile phones, in English and Welsh prisons reflects wider failings in the penal system.
In the 12 months to March 2018, 132 searches uncovered drugs within Preston Prison - up from 83 five years ago.
Over the same period, 21 per cent of the mandatory drug tests conducted in HMP Preston returned a positive result, figures from the Ministry of Justice and Her Majesty’s Prison and Probation Service show.
In total, inmates failed 90 of the 420 tests conducted in the institution.
The most common single drug type found to have been taken in Preston was psychoactive substances, which was found in 50 per cent of samples.
Andrew Neilson, the campaigns director at the Howard League for Penal Reform, said that the finds were symptomatic of wider problems in the prison system.
Reacting to the national numbers, Justice Secretary David Gauke said: “New psychoactive substances (NPS) are a game changer for prison safety, and these statistics reinforce the scale of the challenge.”
“We are addressing this head on, and our £7 million investment in prison security will further bolster defences via airport-security style scanners, improved searching techniques and phone-blocking technology.
“We are also adopting pioneering approaches such as our ‘Drug Recovery Prison’ pilot at HMP Holme House, which is leading the way in tackling the supply of drugs and putting offenders on a long-term path to recovery.”